Plate to plates
- Thread starter andsam
- Start date
I have used dilute hydrochloric acid ('spirits of salts') with some success but DO NOT recommend it because of the risk of starting a leak across the HX. Don't know what ferroquest contains but AFAIR it's supposed to dissolve black oxide. This is usually what you find in the primary half of a plate / plate. Are you actually trying to dissolve limescale in the other half?
It is the black oxide I am trying to dissolve. I have read threads from people saying they never change them and always remove the oxide.I was wondering how they do it and how successful the results are.
Also I have just changed the plate to plate in my Linea so I now have one to practice on. I new I had sludge in the system when I inherited the boiler so I powerflushed the system around september time. Then just after xmas the plate to plate started to fail, so after forking out for a new plate to plate I also installed a Boiler Buddy .I have got to admit Im impressed its only been in a few days and already its collecting deposits.
Also I have just changed the plate to plate in my Linea so I now have one to practice on. I new I had sludge in the system when I inherited the boiler so I powerflushed the system around september time. Then just after xmas the plate to plate started to fail, so after forking out for a new plate to plate I also installed a Boiler Buddy .I have got to admit Im impressed its only been in a few days and already its collecting deposits.
Hang on a tic! If you guys are contemplating hot DS40 /DS3 mixture, I think cold hydrochloric might be a LOT safer and let the plate HX take it's chances of leaking afterwards!
You have to take into account the temperature and strength of the HCl.
The 32% solution is dangerous to handle and for the HX as well.
If its safely diluted to about 5% then its still pretty effective on oxides but has little effect on pure metal at 20*C.
All in all, I do not ever recommend DIYers to use dangerous chemicals. Even DS3 and DS40 are potentially dangerous if used carelessly.
Tony
The 32% solution is dangerous to handle and for the HX as well.
If its safely diluted to about 5% then its still pretty effective on oxides but has little effect on pure metal at 20*C.
All in all, I do not ever recommend DIYers to use dangerous chemicals. Even DS3 and DS40 are potentially dangerous if used carelessly.
Tony
Nope, no and not really.
Hydrochloric acid in any concentration attacks stainless steels. Mechanism is pinholing. Chlorides displace the chromium oxide passivation layer.
Magnet proves Performa plate heat exchanger I have here is austenitic stainless, but I severely doubt it's loaded with molybdenum which would be needed for chloride resistance. It's the cheapest, copper-brazed variety of st st plate h/e. Others may be welded stainless steel, and Chris H found that nickel plated copper one.
Sulphamic (DS-3) citric(DS40, FX-2) and phosphoric (FX-2) acids are used for cleaning stainless steels and would add to the passivation.
No advantage in using them cooler - the cleaning just takes longer. Same is true of lower concentrations, though strong HCl gets more dangerous for other reasons, like it fumes and condenses in stronger concentrations on things.
Hydrochloric acid doesn't attack copper of course, but might have a go at something in the braze material. Also if there happens to be oxygen dissolved in the water, then it'll dissolve copper!
Chlorides in heating systems themseves are seriously bad news.
Caution. Don't try sulphuric acid. a) It won't work and b) it's nasty stuff.
Sodium hydroxide/caustic soda/lye, will also get you nowhere.
Hydrochloric acid in any concentration attacks stainless steels. Mechanism is pinholing. Chlorides displace the chromium oxide passivation layer.
Magnet proves Performa plate heat exchanger I have here is austenitic stainless, but I severely doubt it's loaded with molybdenum which would be needed for chloride resistance. It's the cheapest, copper-brazed variety of st st plate h/e. Others may be welded stainless steel, and Chris H found that nickel plated copper one.
Sulphamic (DS-3) citric(DS40, FX-2) and phosphoric (FX-2) acids are used for cleaning stainless steels and would add to the passivation.
No advantage in using them cooler - the cleaning just takes longer. Same is true of lower concentrations, though strong HCl gets more dangerous for other reasons, like it fumes and condenses in stronger concentrations on things.
Hydrochloric acid doesn't attack copper of course, but might have a go at something in the braze material. Also if there happens to be oxygen dissolved in the water, then it'll dissolve copper!
Chlorides in heating systems themseves are seriously bad news.
Caution. Don't try sulphuric acid. a) It won't work and b) it's nasty stuff.
Sodium hydroxide/caustic soda/lye, will also get you nowhere.
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